Add a mixin for time fields

schema/ent/time_mixin.go

@@ -0,0 +1,27 @@
+package ersteller_ent
+
+import (
+	"time"
+
+	"entgo.io/ent"
+	"entgo.io/ent/schema/field"
+	"entgo.io/ent/schema/mixin"
+)
+
+// TimeMixin implements the ent.Mixin for sharing
+// time fields with package schemas.
+type TimeMixin struct {
+	mixin.Schema
+}
+
+// Fields of the TimeMixin.
+func (TimeMixin) Fields() []ent.Field {
+	return []ent.Field{
+		field.Time("created_at").
+			Default(time.Now).
+			Immutable(),
+		field.Time("updated_at").
+			Default(time.Now).
+			UpdateDefault(time.Now),
+	}
+}